1k0t

<StructureSection load='1k0t' size='340' side='right' caption='[[1k0t]], [[NMR_Ensembles_of_Models | 30 NMR models]]' scene=''>

<table><tr><td colspan='2'>[[1k0t]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Agmenellum_quadruplicatum Agmenellum quadruplicatum]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1K0T OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1K0T FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=SF4:IRON/SULFUR+CLUSTER'>SF4</scene></td></tr>

<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">psac ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=32049 Agmenellum quadruplicatum])</td></tr>

<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1k0t FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1k0t OCA], [http://pdbe.org/1k0t PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1k0t RCSB], [http://www.ebi.ac.uk/pdbsum/1k0t PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=1k0t ProSAT]</span></td></tr>

[[http://www.uniprot.org/uniprot/PSAC_SYNP2 PSAC_SYNP2]] Apoprotein for the two 4Fe-4S centers FA and FB of photosystem I (PSI); essential for photochemical activity. FB is the terminal electron acceptor of PSI, donating electrons to ferredoxin. The C-terminus interacts with PsaA/B/D and helps assemble the protein into the PSI complex. Required for binding of PsaD and PsaE to PSI. PSI is a plastocyanin/cytochrome c6-ferredoxin oxidoreductase, converting photonic excitation into a charge separation, which transfers an electron from the donor P700 chlorophyll pair to the spectroscopically characterized acceptors A0, A1, FX, FA and FB in turn.[HAMAP-Rule:MF_01303] Mutant proteins with a 3Fe-4S center are not observed bound to PSI in vitro, and are probably not able to do so in vivo.[HAMAP-Rule:MF_01303]

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== Publication Abstract from PubMed ==

This work presents the three-dimensional NMR solution structure of recombinant, oxidized, unbound PsaC from Synechococcus sp. PCC 7002. Constraints are derived from homo- and heteronuclear one-, two- and three-dimensional (1)H and (15)N NMR data. Significant differences are outlined between the unbound PsaC structure presented here and the available X-ray structure of bound PsaC as an integral part of the whole cyanobacterial PS I complex. These differences mainly concern the arrangement of the N- and C-termini with respect to the [4Fe-4S] core domain. In the NMR solution structure of PsaC the C-terminal region assumes a disordered helical conformation, and is clearly different from the extended coil conformation, which is one of the structural elements required to anchor PsaC to the PS I core heterodimer. In solution the N-terminus of PsaC is in contact with the pre-C-terminal region but slides in between the latter and the iron-sulfur core region of the protein. Together, these features result in a concerted movement of the N-terminus and pre-C-terminal region away from the F(A) binding site, accompanied by a bending of the N-terminus. In comparison, the same terminal regions are positioned much closer to F(A) and take up an anti-parallel beta-sheet arrangement in PsaC bound to PS I. The conformational changes between bound and unbound PsaC correlate with the differences reported earlier for the EPR spectra of reduced F(A) and F(B) in bound versus unbound PsaC. The observed different structural features in solution are highly relevant for unraveling the stepwise assembly process of the stromal PsaC, PsaD and PsaE subunits to the PS I core heterodimer. Electronic supplementary material to this paper can be obtained by using the Springer Link server located at http://dx.doi.org/10.1007/s00775-001-0321-3.

 

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== References ==

[[Category: Agmenellum quadruplicatum]]

[[Category: Antonkine, M L]]

[[Category: Bentrop, D]]

[[Category: Bertini, I]]

[[Category: Bryant, D A]]

[[Category: Golbeck, J H]]

[[Category: Liu, G]]

[[Category: Luchinat, C]]

[[Category: Stehlik, D]]

[[Category: Solution structure]]